At present the single cone earth boring bit used for boring in oil fields, mining and geological prospecting is composed of a bit body, knobby cones, teeth, sealing members and a lubricating system etc. The teeth and the knobby cone are joined together in form of interference fit. The material for all the teeth are the same, such as hard metal alloy. But owing to the fact that wear of the teeth is not uniform during working of the bits, the teeth in the zone (the permanent contact zone) that contacts constantly with the bottom of a well are worn off so quickly that the working life of the teeth of a boring bit is not matched with that of the bearing, thus affecting the footage of the earth boring bit. Furthermore, as the teeth are worn out, the bit body is likely to be worn subsequently with its diameter being reduced, this would make trouble on further boring after the bit body has been raised.
The object of the invention is to provide a single cone earth boring bit with wear-resistant teeth and bit body gauge blocks which carries active cutting gauge teeth and passive gauge teeth so as to enhance the working life of the teeth and the gauge-protecting effect of the earth boring bit, thereby to improve its footage.